The invention relates to a valve, in particular for fuel tank venting in motor vehicles.
A valve of this kind is disclosed for instance in German Patent Disclosure DE 197 21 562 A1 or German Patent Disclosure DE 40 23 044 A1.
Such valves are used for regenerating adsorption filters for fuel vapor trapping systems for the fuel tank of vehicles. A problem with such valves is that the centering spring can break at high vibration accelerations, which occur in the vehicle especially when a motor is installed and at long valve strokes. The breakage point in most cases is located in the region of the short spring arms, adjacent to the fastening points of the centering spring on the valve member and on the annular gap yoke.
An object of the invention is to refine a valve of the generic type such that even upon a motor mounting of the valve and with the attendant high vibration accelerations, breakages of the centering spring are maximally averted.
In a valve of the type defined at the outset, this object is attained according to the invention by the characteristics set forth herein.
It has been found that by means of the meandering curved course of the short spring arms, a tendency to breakage of the centering spring, even in the region of the short spring arms, adjacent to the fastening points on the valve member and the short-circuit yoke, is decreased considerably.
Furthermore, by fastening the valve member to the short-circuit yoke by means of the centering spring and by means of the embodiment of the centering spring, an especially precise, frictionless guidance of the valve member in the short-circuit yoke/annular gap yoke is made possible, and canting during the clocked operation of the valve is effectively prevented. Without a centering spring of this kind, proper valve function would be impossible, since if the valve member acting as a magnet armature became canted in the annular gap yoke, magnetic saturation would occur at the point of the canting, which would prevent a uniform working motion of the valve member.
In an advantageous embodiment, it is provided that the short spring arms extend in an S-shaped curve.
The fastening of the centering spring to the valve member and to the short-circuit yoke is advantageously done by rivet connections.